The first description of deutonymph and redescription of larva, female and male of the water mite H. nonundulatus Viets, 1919 are given. I reject previous proposals (Lundblad1962 and Di Sabatino et al. 2009) to synonymize H. nonundulatus with H. planus, Thon, 1899.

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phantoidea. Annales Zoologici, 43 (24): 461–492.

Di Sabatino, A., Gerecke, R., Gledhill, T., and Smit, H.
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drachnidia) described from the Palaearctic, part 2:
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